Drive gear for helicopters



M 27, 1949 o. H. BANNER 2,492,831

y DRIVE GEAR Fon HELIGQPTHRS Filed July 5, 1945 4 Sheets-Sheet l e9 l 2y I Y Y v 31 p; 35 ai 75 "l 77 d W e) 25 l||| Illl ,1f 71 i132 7,@ 79 53 74 L E 91 w3 l e@ 65 if #11 ,29228 uw 2 JEL@ Q3 63 54 #Pf 67 a@ 55 l f P6 M11-S` K 25 1 zo Q d ZZWZW.' C 710 cwrj mzer Dec. 27, 1949 o. H. BANKER DRIVE GEAR FOR` HELICOPTERS Filed July 5, 1945 4 Sheets-Sheet 2 SCWKM? fr W, MM M2M Dec. 27, 1949 Filed July 5, 1943 y o. H. BANKER 2,492,831

DRIVE#4 GEAR FOR HELICOPTERS 4' Sheets-Sheet 3 @y ZM, MM, am

Dec. 27, 1949 o. H. BANKER 2,492,831

DRIVE GEAR FOR HELICOPTERS Filed July 5, 1943 4 Sheets-Sheet 4 u,yzfdefzkff @scarl/ 5072 i627.

Patented Dec. 27, 1949 DRIVE GEAR FOR HELICOPTERS Oscar H. Banker, Evanston, Ill., assignor to New Products Corporation, Chicago, Ill., a corporation of Delaware Application July 5, 1943, Serial No. 493,501

11 Claims. (Cl. 74-801) This invention has to do with a power transmission gear having features especially adapting the same for use in the transmission of driving force from the engine to the rotor and steering propellor of rotor-sustained aircraft.

An important object of the present invention is the provision of a lightweight speed reduction gearing employing an engine driven shaft in a coaxial piloted relation with a sustaining rotor shaft and wherein a portion of the sustaining rotor drive shaft between its piloted connection with the drive shaft and a bearing therefor in a casing for the gearing serves as a bearing support for planetary gearing disposed in driving relation between the shafts. This arrangement has the advantage of utilizing an inwardly projecting part of the sustaining rotor drive shaft for laterally stabilizing the same as well as providing the necessary support for parts of the drive gearing, and in this manner lateral support for the driven shaft in the form of an outboard bearing upon the casing is unnecessary. The weight is thereby eliminated both in reducing the size of the casing and in the minimizing of the number of bearings.

Another object of the invention is the provision of a drive gear casing of lightweight metal in combination with an improved means for securing a ring gear of a planetary gear unit thereto:

A further object is the provision of an improved drive gear casing for the reception of an upright lshaft extending inwardly through the bottom of the casing, and including a re-entrant portion about said shaft for holding bearing means in which the shaft is journalled and for forming an annular oil sump in the bottom of the casing.

Another object is the provision of an improved casing having a bottom re-entrant section forming a bearing opening wherein there are axially spaced bearings for the support of a shaft, and a gear pump disposed within the space between the bearing units and having an element secured to and rotatable with the shaft for operating said gear pump.

A further object of the invention is the provision of an improved lightweight gearing employing drive and driven shafts in coaxial relation and a set of serially connected planetary gear units arranged coaxially about one of said shafts and wherein the carrier of one of said units drives the sun gear of the other and said carrier and sun gear being formed integrally to minimize weight. l

An additional object of the invention is the 2 provision of an improved arrangement of an overrunning clutch disposed in driving relation between a drive shaft and the sun gear of a planetary gear unit employed for driving a driven shaft from the drive shaft, and the sun gear and a portion of said overrunning clutch being formed integrally.

Still a further object is the provision of an improved bevelled gear and pinion arrangement for driving a steering propeller power-take-off shaft from the carrier of a planetary gear unit disposed in driving relation between the engine driven shaft and the sustaining rotor drive shaft of a driving gear, whereby the size of said pinion is reasonably small and is serviceable to drive said power-take-oi shaft at substantially the same speed as the engine driven shaft.

Still a further object is the provision of a unique mounting for and disposition of an oil pump in combination with the shaftng and casing of the drive gear unit.

These and other desirable objects inherent in and encompassed by the invention will be more readily understood upon reading the ensuing description -with reference to the annexed drawings wherein:

Fig. 1 is a sectional view taken vertically and centrally through a drive gear constructed according to the principles of the invention;

Fig. 2 is a fragmentary view illustrating vthe manner of attaching and assembling ring gears with the drive gear casing. the View being taken as indicated by the line 2-2 in Fig. 1;

Fig. 3 is a horizontal sectional view taken on the line 3 3 of Fig. 1, showing the arrangement oi gears within an oll pump employed in the device;

Fig. 4 is a view taken similarly to Fig. 1 through a modified form of drive gear;

Fig. 5 is a fragmentary sectional view taken on a vertical plane through a. drive gear casing. illustrating a modined assembly of the ring gear structure and the casing:

Fig. 6 is a horizontal sectional view taken on the yline lof Fig. 5:

Fig.7 isaverticalfragmentarysectionalvlew taken through the sump portion of a casing and taken likewise through a novel oil pump installation contained within the upper end of the drive shaft and disposed below the lower end of the driven shaft; and

Fig. 8 is a plan view of the gears of the pump shown in Fig. 7.

With continued reference to the drawings and particularly to Fig. l, a preferredv form of the invention there shown comprises a casing Il hav- 3 inganupperhalfll andalowerllxglf I2,whiehl halves include peripheral flanges and Il le,- cured together by a plurality of circumferentially spaced bolts llofwhichoneisshown ing. The lower half of the casing wardly turned re-entrant section Il about opening l1 and forming an annular oil sump I8 with the casing side wall Il. An opening theupperendofthecasingupperhalf Il ranged coaxially with the opening I1.

A drive shaft 22extends upwardly into the casing Il throughtheopening I1inwhichsaidshaft hanged coupling member 2l is spllned to the drive shaft 22 at 2t and this anged member 25 is to facilitatecmipling of the drive shafttothesourceofpowersuchasthehellcopter engine. 'A driven shaft 21, which is hollow to minimize weight extends downwardly into the casing Il through the opening 2l. The extreme lower end .of the-driven shaft 2| is piloted within a hollow portion 28 of the drive shaft whereas that portion of the driven shaft just inside of the opening 2l is'journalled within a ball bearing unit 2l. By piloting the lower end of the driven shaft 21 inthesectionnofthedriveshaftwhichkspaced a considerable distance below thelbearing unit 2l, suilicient lateral stabilization for the driven shaft is obtained without extending a portion oi the gear casing upwardly for carrying a stabilizlng bearing unit spacedly above the bearing unit 20. This expedient of carrying the driven shaft in the vertically spaced bearing unit 2l and the pilot bearing 28 in the drive shaft contributes to the compactness of the device and minimizes its weight.

Since the driven shaft 21, when the device is installed upon a helicopter type of aircraft, will carry the sustaining rotor for such craft an lend-- wise downward thrust will be imparted to this shaft by the rotor when the craft is at rest. whereas an upward thrust will be imparted to the shaft during operation of the rotor for lifting the craft. Therefore, the bearing unit 2l is imtalled in such a manner between the shaft 21 and the casing as to withstand extreme end thrusts upon the shaft in either direction. 'I'he inner race 3| of the bearing unit 29 is xed against endwise movement upon the shaft 21 by means of a shoulder 32 thereon and a nut 33. The outer race 34 of said bearing unit is carried in a ring I5 which has a flange 36 in abutment with the upper end of the casing and against which the upper end of said race is held by a clamping ring 31 which is Y secured in place by bolts 28.

The drive snafu zz is similarly nem against ax- A ial movement within the casing by the bearing unit 23 of which the inner race 39 is clamped onto said shaft between a hub portion 4I of a pump gear 42 (later to be described) and the hub of the coupling member 25. A shoulder 43 on the drive shaft serves as an abutment against which the parts 2i, 3l and 42 arepreslcd by a nut 44 when the latter is turned onto a threaded end portion 4i of the drive shaft. Axial movement of the outer race 46 of the bearing unit 22 is prevented byaflange 41 onaring whichisaxiallyxed in the re-entrant portion it of the'casing and by meansofaringuwhichissecuredtothering 48 by cap bolts 5|.

Gearing employedbetween the drive shaft and the driven shaft consists of two planetary gear units generally respectively designated l2 and I3 which are connected in series driving relation. 'I'he lowermost of these planetary gear units comprises a sun gear I4 arranged coaxially with the drive and driven shafts and having a hub extension It journalled at It upon a section of the driven shaft 21.- This extension 5i of the sun gear 54 is made in the form of a roller actuator l1 for the rollers Il of an overrunning clutch Il which also comprises the usual ring Il, formed integrally with the drive shaft, against which the rollers Il are wedgeable in frictional drivin relation by said actuator member when it is rotated in one direction. In the present instance it may be assumed, for example, the actuator member I1 is so formed as to cause the rollers 5l to wedge into frictional driving relation with the ring il when said ring tends to rotate counter-clockwise with respect to said actuator member, as viewed from an observation point below Fig. l. Clock- .wise rotational tendencies of the ring l can occur without incurring wedging of the rollers and relatively to said actuator member and therefore without imparting driving force to the sun gear I4. It follows that the sun gear 54 may rotate counter-clockwise as viewed from below relativelytotheringil while overrunningtheoverrunning clutch 5l, and this condition is desirable to have prevail in such an instance as when the engine may cease operating while the craft is in flight wherefore the sustaining rotor can windmill for causing the craft to descend at a nonprecipitous rate.

'Ihe sun gear 54 of the lower planetary gear unit meshes with a plurality of planet gears I2,

of which one is shown in Fig. l, distributed cir-,l

cumferentially thereabout in the usual manner and `iournalled upon hollow bearing members Il disposed upon and revolvable about the axis of a carrier 64. The hub 8l of the carrier t4 is formed integrally with a sun gear 66 of the planetary gear unit 53 which is also journalled upon the driven shaft 21. 'I'he planet gears 62 mesh with a ring gear t1 which is secured to the casing by a plurality of circumferentially spaced bolts 6l. These bolts 68 also serve to secure a ring gear 69 of the planetary gear unit 53 to the casing in a manner presently described in detail.

The carrier 1I of the upper planetary gear unit has circumferentially spaced hollow bearing members 12 similar to the bearing members 63, and the planet gears 13 of this upper planetary gear unit respectively journalled on said bearing members mutually mesh with the sun gear 66 and said ring' gear t9. The carrier 1l ist splined to thedriven shaft 21 as indicated a 14.

The lower edge of the upper ring gear BI has a plurality of circumferentially spaced bosses 1I, one being shown in Fig. 2, of which each has a notch 16. Similar bosses 11 are formed on the upper edge of the ring gear 61 and contain notches 18. These notches 16 and 1l have the same width as do square heads 19 on the bolts Bl. Before assembling the upper half of the casing with the lower half, the ring gear il will be inserted into the casing upper half Il sumcientlyv far to place the upper edge of said gear against a shoulder Il of said casing upper half.

The gear will be so rotativelyv positioned as to bring its notches 16 into respective registry with holes I2 in such casing upper half for the bolts 6l. The width of the bolt heads 1I are so chosen that when the bolts are inserted through the holes l2 the upper edges of `their heads will fit snugly against the ceilings of the notches 1t for retaining thegear Ilrmly against the casing 1 5 shoulder 8l.' The ring gear 61 is so rotatively :incassi serve to press the lower edge of the ring gear 81 against the casing shoulder 88. Therefore, the bolt heads 19 cooperate with the shoulders 8| and 88 of the assembled casing in preventing axial displacement of the ring gears 51 and 89, and these bolt headscooperate with the notched expedient of stepping down the speed of the bevelled gear 85 which drives the same. this speed reduction of the drive pinion 85 being obtained through the primary planetary gear unit 52. The speed of the driven pinion 92 is stepped back up to the desired speed for the shaft 81 by bosses and 11 on the ring gears for prevent- 1 ing rotation of these gears. In the operation of the gearing so far described, clockwise rotation, as viewed from below, will be imparted to the drive shaft 22 from the aircraft engine. This shaft rotates freely in the bearing units 29 kand 24. Rotative force is imparted to the lower sun gear 54 through the overrunning clutch 59, and this rotation of the sun gear 54 causes planetary movement of the planet gears 82 meshed therewith while they react against the xed ring gear 81. Thus the primary carrier 84 is caused to rotate at a reduced speed with respect to the drive shaft and the sun gear 54. The secondary sun gear 85 which is formed integrally with the carrier 84 will therefore likewise rotate at a reduced speed and will cause planetary movement of the planet gears 18 meshed therewith while they react against the fixed ring gear of the secondary planetary gear unit. Thus the secondary carrier 1| and the driven shaft 21 splined thereto are caused to rotate at a further reduced speed with respect to the driving shaft.

A power take off for driving the steering and stabilizing propeller of a helicopter upon which the device is adapted to be installed receives driving force from a bevelled gear 85 which is secured by bolts 86 to and for rotation with the primary planet gear carrier 64. A power take off shaft 81 is journalled within axially spaced bearing units 88 and 89 in an outboard section 9| of the casing, and the inner end of this shaft 81 has formed thereon a bevelled pinion 92 which meshes with the bevelled gear 85. A tachometer drive shaft 93 is adapted to be driven from the power take oif shaft 81 through a worm gear 94'and a worm pinion 95 respectively fixed to the shafts 81 and 98.

It is desirable that the power take off shaft 81 for supplying driving force for the steering propeller of the helicopter rotate at substantially the same speed as the drive shaft 22. Normally the substantially one-to-one Adriving speed ratio of the shafts 22 and 81 could be obtained by means of moderately sized lbevelled gears of the same diameter meshed with one another and ilxed respectively upon these shafts. However, because of the drive shaft. 22 being encased within the re-entrant portion I8 of the casing and because of the upper end portion thereof being enlarged to form the ring for the overrunning clutch 59, a driving bevelled gear upon the accessible portion of the drive shaft would have to be quite large and thereby require a correspondingly and prohibitively large driven pinion corresponding to the pinion 92. In the present embodiment the moderate sized driven pinion 92 is operable to drive the power take on shaft 81 at the desired speed by employing the reducing the diameter of said pinion 92 with respect to the diameter of the drive gear 85. In other words, there is a speed reduction to theI large diameter drive gear and a speed step up from the more slowly rotating gear 85 to and through the moderately sized bevelled pinion 92 whereby the power take oif shaft 81 is caused to rotate at the desired speed.

Connectingv the steering propeller shaft 8 1 with the sustaining rotor shaft 21 above the overrunning clutch 59 provides for these two shafts always being drivingly connected whereby in case of engine failure the steering propeller shaft will be driven by force derived from the sustaining rotor of the descending craft. vTherefore,y the dirigible feature of the craft will be preserved for use in an emergency landing.

The lubricatingoil for the device is poured into the sump I8 through a casing opening 95 normally closed by a screw plug 91, it being understood that the drive gear unit operates in the upright position shown in Fig. 1, with the sump i8 at the bottom. This oil is forced to strategic bearing surfaces of the device by a pump 98 which is disposed about the drive shaft within the space provided therefor between the drive shaft bearing units 29 and 24. currently to Figs. 1 and 3` the pump 98 will be seen to include the aforesaid gear 42 fixed to and for rotation with the drive shaft 22. This pinion gear has lobe-like teeth 99 which are meshable with lobe-like internal teeth |88 upon a gear |8| which is arranged eccentrically with respect to the gear 42. The gear |8| has a circular outer surface |82 journalled within the pump casing |88 and has radial ports |84 which communicate between said circular surface |82 and the internal spaces between the teeth |88. A portion of the casing |83 lies flatly over the upper end faces of the pump gears 42 and |8| excepting for a discharge port |85 shown in full lines in Fig. 1

and indicated by dot-dash lines in Fig. 3. The? bottom faces of the pump gears are engaged and sealed by an annular bottom plate |88 secured to the casing by bolts |81.y An inlet passage |88 communicates with the outer ends of the radial passages of the driven gear |8| during a portion of the rotation of said gear |8|. This inlet channel |88 communicates with the gear casing sump I8 through a radial passage |89 in th'e pump cas. ing |83, a channel I I8 in the lower half I2 of the gear casing, and a filter member removably contained ina bottom section ||2 of said casing as I2.

clockwise direction as viewed from below, the pump gears 42 and |8| will be caused to rotate in the direction of the arrows shown thereon in Fig. 3, the gear 42 driving the gear |8| while the latter rotates eccentrically thereof within the casing |88. While the pump gear teeth traverse that portion of their rotative paths which is in radial registry with that portion of the intake channel |88 between the channel |89 and the lower left end of said channel |88 as viewed in Fig. 3, the space between the teeth on the gears will be increasing thereby increasing the volume of the space contained therebetween so that the Referring con- During rotation of the drive shaft 22 in the y suction occurs drawing oil through the filter member III and upwardly through the channel III. and inwardly through the channels III and III and through the radial passages III into the space between the toothed portions of the gears. As these filled spaces between the gears traverse that portion of their path which is in registry with the casing port III. the space will be contracted to force the oil from between the gears upwardly into the port and thence radially inwardly through holes III in the drive shaft and thence into the hollow portion of said drive shaft.

Part of the oilthus forced into the hollow drive shaft under pressure is forced upwardly for lubricating the bearing sleeves III and III respectively between the lower piloted end of the driven shaft and drive shaft and the driven shaft and the overrunning clutch actuator I1. 'I'his oil will leak outwardly from the upper end of the sun gear I4 and thence back into the casing reservoir. Some of the pumped oil will be forced upwardly through the hollow portion of the driven shaft 21 where it is maintained under pressure by a closure cup III and thus forced radially outwardly through radial holes |I1 in said shaft. Oil forced through the holes I I1 lubricates a bearing sleeve I II for the common hub of the primary carrier 64 and the secondary sun gear 66. Some of the oil is forced outwardly through holes (not shown in the bearing sleeve III) and thence through holes III (one being shown) in the hub of the carrier Il and into an annular passage |20 from which radial channels I2I extend (one channel being shown) respectively to the hollow shafts I3 for the planet gears I2, for lubricating bearing sleeves |22 between these shafts and their respective planet gears. The oil is introduced into the hollow shafts Il from the channels I2| through holes |22 and is trapped under pressure within these shafts by integral end walls |24 at one end thereof and closure caps |25 at their other ends. This oil reaches the bearing sleeves |22 through radial passages |26 in the hollow shafts. The excess oil leaks from the ends of the bearing sleeves |22 back into the casing sump.

Additional radial passages, |21. in the driven shaft 21 conduct the oil radially outwardly for introduction into the hollow planet shafts 12 through radial passages |2I and I2I. These planet shafts 12 have an integral upper end wall and a lower end cap III for closing their ends whereby the oil introduced thereinto may be forced outwardly under pressure through radial passages |32 for lubricating the planet bearing sleeves |32. The oil leaks endwise from these bearing sleeves and is thence thrown centrifugally into the casing where it ultimately drains back to the casing sump II.

An important advantage of the ring gear mounting within the casing is that the ring gears I1 and I! are adapted to be formed of hardenable steel while the casing is adapted to be made of a light weight metal, thereby minimizing the overall weight of the device which is an important factor in equipment for installation upon aircraft. Another important advantage which has to do with the reduction of weight is the utilization of the hollow upper end of the drive shaft for journal piloting of the lower end of the driven shaft and thereby cooperating with the upper bearing unit 29 in providing axially spaced stabilizing bearing supports for the driven shaft, making it unnecessary tov extend the casing above 8 the bearing unit 2l for the support of additional bearing means spaced from the bearing unit 2l for giving adequate stabilizing support for the driven shaft. That part of the driven shaft extending downwardly into the casing also provides Journalling for the secondary sun gear II and the primary carrier 64 as well as for the primary sun gear 5I and the overrunning clutch actuator I1. This double use of the downwardly extending portion of the driven shaft 21, that is, its use as journal support for parts of the planetary gear units and stabilizing bearing means for said driven shaft. expediently utilizes the material used in the ccn struction of the device so that its weight is desiryably small; The weight factor is also aifected favorably by making the secondary sun gear II integral with the primary carrier I4 and by mak. ing the primary sun gear Il integral with overrunning clutch actuator l1.

The second form of the inventionl shown 'in Fig. 4 is for the most part constructed like the above described first form, and to expedite this description those parts which are identical with or which substantially correspond to respective parts in the rst form are simply designated by the same respective reference characters with th addition of a prime.

One difference in the second form of the invention is the integral construction of the primary and secondary ring gears I1' and II. This integral structure of the ring gears I|'II has an outwardly projecting radial ange III which is adapted to be clamped between the upper and lower halves II' and I2' of the gear casing. Holes |52 in the flange III register with holes III and |54 in horizontal flange portions of the casing halves for the reception of bolts III which are adapted for holding these parts in rigid assembly.

Another difference of significance in this second form of the invention is the manner in which the bevelled gear is attached to the primary carrier I4. This bevelled gear II' has an upwardly extending cylindrical portion III which is suitably attached to the carrier I4 while the bevelled gear proper is journalled upon the reentrant lower wall portion II' of the casing. there being bearing sleeves |51 and |58 interposed beftween the gear I5 and said casing re-entrant portion. This arrangement of the gear Il' relieves reactive force taken from the driven pinion 92' from the hub 65 of the primary carrier I4'. A more solid support is also provided by the reentrant casing portion I6 for the bevelled gear 85'. Furthermore, the bevelled gear I5 is placed suciently far below the primary planetary gear unit to facilitate disposal of the driven pinion I2 above said gear 85', making possible a dierent and wider range of angular positions with which the power take olf shaft 81' may be disposed with respect to the axes of the drive and driven shafts 22 and 21.

In Figs. 5 and 6 a still dierent form of ring gear structure and assembly thereof with the gear casing is shown. In this form the parts corresponding to those in Fig. 1 are designated by the same respective reference characters with the addition of a double prime. The integrally formed priman,7 and secondary ring gears I1" and II". rest upon a shoulder I3" in the lower casing half I2. The upper end of the integral gear structure 61"-68 is provided with a plurality of notches III which receive radial projections II2' extending radially inwardly from a ring II2 which is clamped between flanges III and III of the casing by means of bolts |08. The projections |02 in addition to preventing rotation of the ring gear unit GTL-69" further serve cooperatively with the shoulder 83" for preventing axial displacement of this integral gear structure.

A novel oil pump arrangement is shown in Figs. 'I and 8. The oil pump generally designated 20| is contained within the upper hollowed portion of a drive shaft 22" in which the lower end of a driven shaft 2l" is piloted upon roller bearings Il". Those parts Just identified by the reference characters with the double prime correspond to parts shown in Fig. 1 identified by the same respective reference characters without the double prime. Other reference characters in Figs. 7 and 8 incorporating the double prime exponent have the same significance with respect to reference characters and parts designated thereby in Fig. 1. Thus the sump I8" contains an oil filter through which oil is strained prior to being drawn into the pump 20|.

Said pump 20| comprises lobed eccentrically journalled pinion and ring gears 42" and |0|" corresponding to and cooperative similarly to the gears 42 and |0| in the Fig. 1 embodiment. A casing |03" for the pump 20| is gener-ally cupshaped and has a cylindrical outer periphery. This casing |03 is fitted into the hollow section of the drive shaft22" where rotation relatively thereto is prevented by a key 200. Inlet and outlet ports |09" and |05" are formed in the bottom of the casing |03", the inner and upper ends of these ports leading respectively into the bottoms of arcuate recesses |08 and 202. Inlet port |09" as seen in Fig. 7 extends entirely downwardly through the casing member |03 where it communicates with a space 203 between the bottom of the casing and the bottom of the hollow section in the drive shaft 22" and thence continues communication through one or more radial passages 204 with an annular chamber 205 formed between oil seals 225 and 226 and the re-entrant portion HH of the casing |2".

An internally threaded downwardly extending portion 206 of the casing |03" contains a threaded plug 201 which forms a reaction member for one end of a spring 208 forming a part of a pressure relief valve 209- which also comprises a ball 2| 0 urged against a ball seat 2|| by said spring 208. When the ball 2|0 is held against the seat 2|| pumped oil is precluded from escaping from the outlet port |05 through a port 2|2 in said seat and thence through a second port 2|3 into the low pressure space 203. A circular bearing |02" in the pump casing for the internally lobed gear |01" is arranged eccentrically with respect to the transmission drive and driven shaft axes. The internally lobed gear |0|" is adapted to rotate freely within the bearing |02. The lobed pinion gear 42 is keyed at 2| 4 to a hollow shaft 2|5 which is coaxial with the transmission shafts 22" and 2'| and eccentric to the pump gear |0I" as shown in Fig. 8. Pinion shaft 2 5 is journalled in a bearing 2|6 in the pump casing |03" and in a bearing 2|`| in an upper end plate 2|8 of such casing. This casing end plate 2|8 has a flat under side fitted in sliding sealed relation with the upper end faces of the pump gears and is retained in this position by a snap ring 2|9 expanded into a groove 22| in the transmission drive shaft. A ring 222 press-fitted in the lower end of the transmission driven shaft contains a shear pin 223 which is within a notch 224 across the upper end of the pump pinion shaft to constrain the pump pinion 42" `and said shaft, 2| 5,

for rotation with the transmission driven shaft. Thus the pump pinion is caused to rotate at a speed reduced with respect to the pump casing which rotates with the transmission drive shaft.

In the operation of this pump when the drive shaft 22" and the pump casing rotate clockwise, as viewed in Fig. 8, the transmission driven shaft 21", pump pinion shaft 2 |5 and the pump pinion 42" are also rotating clockwise but at a reduced speed wherefore the pump pinion is rotated counter-clockwise with respect to the pump casing. Since the pump pinion is meshed with the pump ring or rotor gear the latter will also be caused to rotate in its bearing |02" counterclockwise with respect to the pump casing. During this rotation of the pump gears counterclockwise relatively to the pump casing the latter, while rotating eccentrically about the pump pinion axis, maintains the arcuate recesses |08" and 202 and the inlet and outlet ports |09" and |05" oriented as shown in Fig. 8 with respect to the coincidence point of the pump gear tooth pitch circles. Therefore, as theA pump teeth in rotating counterclockwise relatively to the casing traverse that portion of their paths in registry with the inlet recess |08" the space between the pinion and rotor gear teeth will be expanding to suck oil into the pump from the sump I8 through the filter annular chamber 205, holes 204, space 203, inlet port |09", inlet recess |08" and into such expanding space between the pump teeth. Subsequently as these pump teeth traverse that portion of their path in registry with the outlet recess 202 the pinion and rotor teeth are forced together, vexpelling the oil outwardly through the recess 202, and a radial lateral 226 thereof and thence upwardly through the hollow pinion shaft 2|5 from which it is discharged into the hollow transmission shaft 2l" for distribution to lubrication points in the transmission shafting and gearing. Should the discharged passages for the pumped oil become clogged, excessive pressure is prevented by the opening of the relief valve 209 and the escape of the oil into the low pressure space 203.

While I have herein shown and described but a limited number of embodiments of the invention, it will be understood that the invention extends to other embodiments, forms, modifications, structures and details falling within the scope and spirit thereof and not sacrificing all of its material advantages.

I claim:

1. In a helicopter drive gearing, a gear casing having a lower drive shaft bearing and an upper driven shaft bearing axially aligned with the drive shaft bearing, a drive shaft journalled in said drive shaft bearing, a driven shaft journalled in the driven shaft bearing and extending downwardly into piloted relation with the driven shaft, said driven shaft having a rotatable part bearing portion within said casing between the driven shaft bearing and the drive shaft, and means for establishing a driving connection between said shafts comprising a planetary gear unit including a sun gear journalled on said driven shaft bearing portion, a ring gear fixed to said casing, a carrier drivingly connected with the driven shaft and planet gears journalled on the carrier4 and meshed with the sun and ring gears, and an overrunning clutch arranged coaxially with and disposed in driving relation between said drive shaft and said sun gear.

2. In a helicopter drive gearing, a gear casing having a lower drive shaft bearing and an upper accessi il l2 drivenshaitbcsringaxiallyalignedwiththedrive llidrillearsagaimtmteonrelativeiytothe bcaring.` shaft journalled in said casing. l driveshaitbearingadrivenshaftjournalledin 5.Thecombinationsetforthinclaim4and the driven shaft bearing and extending downwhereinsaidissteningportionscomistofnotchcd wardlyintopilotedrelationwiththedriveshaft, g bosscsextendingaxiallyfromtheinnerendsoi saiddrivenshafthsvingarotatablepartbearing saidringgearawhereinthebooneachgear portionwithinsaidcasingbetweenthedriven registerwithrespectivebosscsontheother,and slnftbearingandthedriveshsftandmeansior whereinsaidbosshavenotchopeningendcstahlishmadrivingconnectionbetweensaid wisefromtheirrespectivegearsandcoopersble shaftscomprkingaplanetarygearunitincluding le with the notches in the respectively opposed apairofpianetarygrnnitsdisposedinsuperbosscstoformweningsforthereceptionoiiasrelationaboutsaiddrivenshaitbearing ienimmeanlcommontheretoandforextending fhelowerofsaidunits constitutinga therethrohsndthroughthecasingforretainunitandtbeupperthereofasecondary instheringlearslsainstsaidshouldersandior unit,saidunitscomprhingrpectlvesungears 1g holdimsaidgrsagainstrotationrelativelyto ionrnalledonthe drivenshait bearing portion, thecasing.

respectiveringearsilxedtothecasing.respec 6.Inalightweightaircraftdrivegearlng,a tivesebofplanetgearsmeshed with their assocasingmadeof avrel/ativelylightmetal and having cia w sections disposable axiallytobil. the lower-most of said seci bearing opening and connected for rotation with the driven sha A c sectiom having a driven shaft theearrieroftheprimu'yunite-be" y the sun gear ofthe into the casim respectively through said unit, 'and an overrnnning clutch compris 1 l' openingsandhavinginnerendsinpilotedrelation driving element upon the upper 'end o with oneY another, "planetary gear meam connected between and for transmitting driving force driven shaft bearing, 0.and formed intebetween said shafts, said planetary gear means grallywiththeprnnaryuiit'slmgear. inoludingaringgearsecuredtothecasing,and

3.1n a lightweight aircraft drive gearing, a 30 meenSfOrSeeurinsSeidririsseriiOiiheeins casing made of a relatively light metal and havcomprising a ilange projecting radially from said ing upper and lower sections disposable axially gear between said casing sections and fastening together' into assembly, the lowermost of said means extending mutually through said casing sectiom having a drive shaft bearing opening sections and said ange for holding said casing andtheupperofsaidscctlonshavingadriven g5 sectionsinsaidringgearinassemblyand for shaft bearing opening, drive and driven shafts prevenu!!! millon 0f Seid r11-is Beer relatively extending into the casing respectively through to the casing. said and having inner ends in piloted '1. m a lightweight aircraft drive gearing, a relation with one another, planetary gear means casing made of a relatively light metal and havconnected between and for transmitting driving 40 i118 Upper end levier Seetins disveble M1811! forcebetweensaidshaits said planetarygear together into assembly, the lowermost of said secmeamineiudingarlnggearsecuredtothecasing, tienshavinsadrive shaftbearingopeningand and meam for securing said ring gear to the the upper of said sections having a driven shaft casing comprking an abutment means upon one beei'ins Upening. drive and driven shafts extendoi' said casing sectiom engageable with an end 4,5V ins into the easing respectively thrilgh Seid of said ring gear, a fastening portion extending 01101111188 end having inner end in pilied releaxiany from the other end or said ring gear edtien with one another. planetary gear means jaeently to the casing and fastening means -exwnnected between and for transmitting driving tending thremrh seid fastening portion and seid foree between seid shafts; said manetary sur casing for retaining the ring gear against said 60 means includingarlnggearsecuredto the casing. shoulder and for holding said gear against rotaand means fOr Securing Seid ring gear t0 the tion relatively to the casing. A casing comprising an annular seat for said ring 4. In a lightweight aircraft Adrive gearing, a sear in one of said Sections, Seid seat being casing made of a relatively light metal and haveble with an end 0f Said gear. axially exing upper and lower sections disposable axially 55 tending bow upon the other end of said gear. together into assembly, the lowermost of said an intsriorly notched annular member. said anscctions having a drive shaft bearing opening and nular member being disposable between the cas-- the upper of said seennm having a driven shaft ins sections with its notched inner -periphery bearing opening, drive and driven shafts extendmashed ,with the bosses on said ring gear t0 Dreing into the casing respectively through said s0 vent rotation thereof,and with a portion of said openims and having inner ends in piloted relaannular member bearing against said. other end tion withone another, planetary gear means conof the gear for holding its one end against said l nectedbetweenandfortmnsmitting driving force seat, and fastening means extending through between said sham, said planetary gear means said casing sections and said annular member for including axially spaced ring gears secured to d5 holding said sections and member in rigid asthe cssing,and meam for-securing said ring gears sembly.

to the casing comprising opposed seating means 8. In combination, coaxial relatively rotatable rcspcctivelynpon said'casing sections for respecshafts, one of said shafts having an end recess in tiveI )yiiheiniterandoppositeendsl whichanendoftheothershaftisdisposedsaid o( said ring gears, i portions extending 70 othershafthaving an outlet duct leadingaxially axiallyomtheowcdinnerendsofsaidring thereintofromsaidendthereof,andagearpump gearsadimeentlytothecasing,andfastening betweensaidshafts,comprisingacasingrote meansextemiingthronghsaidfasteningportions tivelyilxedintherecessofthe one shaftssid sndsaidcasingforretainingsaidringgears casinghavlngacylindricalbearingwalldisposcd sgainsttheirrpectiveshmildersandforholdlng 75 with its axis in eccentric parallelism with the 13 shaft axes, an internally lobed pump rotor gear journalled in said cylindrical bearing wall, a lobed pinion gear disposed within the rotor gear coaxially with. said shafts and constrained for rotation with said other shafts, said pinion gear being of a diameter to mesh with the rotor gear at one side thereof and to dispose lobes thereof -diametrically opposite to those meshed with the rotor gear in sealing wiping relation with lobes of the rotor gear at substantially its diametrically opposite side to form pockets between the lobes of said gears upon opposite sides of a median line passing through said sides of the rotor gear, said casing having end walls respectively in sliding sealing relation with the ends of said gears, outlet duct means in said casing communicating between one of said pockets and the outlet duct in said other shaft, and inlet duct means in said casing communicating between the other of said pockets and the recess in the one shaft, and said one shaft also having an inlet duct communicating with its recess, a 'pressure relief duct in said casing between said outlet duct therein and the one shaft recess, and a pressure relief valve comprislng a spring-pressed element in said pressure relief duct, a spring chamber projecting axially from an end of the casing into said recess of the one shaft, and a spring in said spring chamberv for pressing said spring-pressed element.

9. In a helicopter drive gearing, a gear casing having a lower drive shaft bearing and an upper driven shaft bearing axially aligned with the drive shaft bearing, a drive shaft journalled in said drive shaft bearing, a driven shaft journalled in the driven shaft bearing and extending downwardly into piloted relation with the drive shaft. said driven shaft having a rotatable-part receiving bearing portion within said casing between the driven shaft bearing and the drive shaft, and means for establishing a driving connection between said shafts comprising gearing including a pair of planetary gear units disposed in superposed relation about said driven shaft bearing portion, the lower of said units constituting a primary unit4 and the upper thereof a secondary unit, said units comprising respective sun gears iournalled on the driven shaft bearing portion, respective ring gears fixed to the casing, respective sets of planet gears meshed with their associated sun and ring gears and respective carriers upon which said sets of planet gears are journailed, said carrier of the secondary unit being connected for rotation with the driven shaft and the carrier of the primary'unit being rotatively nxed with the sun gear of the secondary unit, and an overrunning clutch comprising a driving element upon the upper end of the drive shaft and a driven element iournalled upon said driven shaft bearing portion and constrained for rotation with the primary unit sun gear.

10. In a drive gearing unit for a helicopter having a body portion and a supporting rotor, the combination of coaxial upper and lower shafts, said upper shaft being adapted for connection with the supporting rotor and having an enlarged splinedV portion, two stage planetary gearing forming a driving connection between said shafts, said gearing including an upper planet carrier having a hub mounted on said splined portion. a thrust bearing mounted on said shaft above said hub and confining said hub against upward movement, a housing for said gearing supported upon said thrust bearing and adapted to transmit the weight of the helicopter body portion to said thrust bearing. a thrust bearing by means of which the lower end of said lower shaft is journaled in the lower portion of said housing, said planetary gearing including an upper sun gear and a lower planet carrier supported by the upper end of-said lower shaft for rotation, a sun gear coaxial with and driven from the upper end of said lower shaft, and ring gear means carried by the housing.

11. The combination set forth in claim l, wherein the drive shaft has a bell-shaped upper end portion forming a driving element of said overrunning clutch, and ywherein the driven element of said overrunning clutch is journalled upon said bearing portion of the driven shaft and formed integrally with said sun gear.

,OSCAR H. BANKER.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 733,600 Schneible July 14, 1903 986,588 OKelly Mar. 14, 1911 1,217,427 Fast Feb. 27, 1917 1,299,156 Fast Apr. 1, 1919 1,320,530 Buehler Nov. 4, 1919 1,497,050 Wardwell June 10, 1924 1,840,867 Rayburn Jan. 12, 1932 1,882,383 Hallitt Oct. 11, 1932 1,945,361 Ball Jan. 30, 1934 1,960,141 DAscanio May 22, 1934 1,960,512 Roos May 29, 1934 1,977,943' Gianini Oct. 23, 1934 2,041,796 Stalker May 26, 1936 2,053,919 Pigott Sept. 8, 1936 2,156,603 Nardone May 2, 1939 2,269,916 ,Price Jan. 13, 1942 2,271,640 Heintz Feb. 3, 1942 2,318,276 Worthington May 4, 1943 FOREIGN PATENTS Number Country Date 476,561 France May 18, 1915 

